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Injecting Advice

Flushing Causes Damage

Written by Nigel Brunsdon on . Posted in .

Anyone who has spent time with people who inject drugs or seen the footage from Avril Taylors study on injecting drug use will know ‘flushing’ is a major issue. But is it something we often talk about? And how can we make people easily understand the issues when we do?

What is ‘flushing’

When someone is injecting they pull back slightly on the plunger to check they are correctly placed in the vein, this is of course a good thing. However the main word in the above sentence is ‘slightly’ what we see happening in a lot of injectors is pulling back a large quantity of blood into the barrel. This is usually done either at the end of injecting and/or part way though the injection.

Why do people ‘flush’

There are three main reasons that people think flushing is necessary:

  • To repeatedly check that the needle in still in a vein
  • To ‘push’ the drug around the body faster
  • To make sure that all the drug is in the vein

All of this is unnecessary, modern syringes are designed to deliver 100% of the drug they contain. Even if these was a small amount of drug still in the barrel/needle it would be minuscule. Blood is constantly on the move in the body so the ‘pushing’ effect will do nothing at all. I do understand the perceived need to check half way though injecting that you are in the vein, but in reality this will just increase the chances of coming out of it.

What’s the problem with flushing

Every time you pull back on the syringe you’re going to cause the needle to move. Of course this means that the needle may come out of the vein you’re using, but it can also make it strike/scratch the other side of the vein itself. This increases scaring on the vein which in turn speeds up the collapse of the vein.

Another issue is that veins have valves. These valves break the vein down into small sections and when people are pulling back on the plunger these sections of the vein contract slightly again causing the needle to strike/scratch the vein wall.

How to explain this

I personally use many ways to explain this while I’m training or in the NSP eg

Imagine you have a drinking straw and you block up one end while sucking the other, the straw collapses, to some extent this will happen to a vein because of the valves it contains.

I’m also a big fan of the hastily drawn diagram, we even have a whiteboard in the NSP to make it easier. If you draw an image of a a vein with valves, or the build up of scaring leading to collapse it’s easier for people to understand. I think drawing it can even be more useful than having a ready made handout as it makes the intervention more personal and so has a greater impact, although ideally using a sketch to get the point across then a professional leaflet to take away would be ideal.


Flushing is seen as totally normal and expected by most injectors, so any advice you give will be going up against the advice of people they trust far more than they trust you you.

The risks of damage increase when injecting cocaine/crack because it causes contraction of veins and a has a local aesthetic affect. If someone can’t feel the area they are injecting then they have real problems knowing if they are still in the vein, and so are more likely to want to check. Stimulant injecting is also something that can also lead to more compulsive behaviours and as a result changing flushing habits becomes harder.

But with both these points, just because something is hard to do doesn’t mean we shouldn’t try.

Writer: Nigel Brunsdon

Nigel Brunsdon is the owner of Injecting Advice. He’s been working in harm reduction since the 1990’s, previously a frontline needle programme worker he now splits his time between photography and developing online resources for drugs workers and users.

Nigel Brunsdon

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